Ken Walton

For cellist Steven Isserlis, the Brahms Double Concerto is all about friendship. So playing it with one of his best pals – American violinist Joshua Bell – is about as good as it gets. “We’ve known each other for almost 30 years,” says Isserlis. “He’s like a younger brother.”

They are together again at the Usher Hall in Edinburgh tomorrow. Bell, music director of the Academy of St Martin in the Fields, is in the driving seat for an entire orchestral programme that includes music by Dvořák, Schumann and Beethoven. And he’ll feature as soloist himself in Benjamin Britten’s stand-alone reworking of the slow movement from Schumann’s Violin Concerto. Britten created this version with specially added codetta in memory of the great English horn player Dennis Brain, who died tragically in a car accident in 1957. It has lain unperformed since 1958.

Isserlis discovered the score among the Britten Archives. He brought it to Bell’s attention, even suggesting a role for himself. “There’s that big cello melody in the slow movement,” he explains. “It’s not actually marked solo, but I’m going to play it solo.” It will make a fitting prelude to the Brahms Double.

And what of the friendship theme that Isserlis mentions in the Brahms? “Unusually for late Brahms, it has hidden messages in it,” he says. The concerto was written at a time when the composer had not been speaking to Joseph Joachim, the violin virtuoso responsible for premiering the earlier Violin Concerto and generally championing Brahms’ cause. So what had gone wrong between the two musical giants?

“They’d fallen out over Joachim’s divorce from his wife,” says Isserlis. “Brahms stuck up for the wife, which didn’t go down well with Joachim, so Brahms wrote the Double Concerto as a peace offering. In the second bar, for instance, he makes a coded reference to Joachim’s motto [the notes F, A and E, standing for “Frei aber einsam” or “free but alone”, that Brahms and Schumann had conceived for their friend]. It also happens to be a reference to Viotti’s Violin Concerto No.22, which Brahms knew to be a favourite of Joachim’s.”

But there are more telling gestures, says the cellist. “You hear this pleading of the violin alongside the gruff cello at the beginning, then sudden silences, as if an old friendship has been ruptured. Brahms admits as much, and more, in his letters; there are all sorts of opportunities for private jokes.” Isserlis and Bell have been sharing them almost exclusively in this piece. “I did it with Josh three years ago with this orchestra, and I’ve not really done it much with anybody else,” he says.

As for Isserlis’ friendship with Scotland – and it’s only a few weeks since he was last here, playing the Schumann Cello Concerto with the Scottish Chamber Orchestra – that goes back even further than his association with Bell. At the age of 14, he was taken out of school in London and packed off to rural Berwickshire to study for three very formative years with leading cello teacher Jane Cowan, who had already been teaching him from the age of 10.

“These were very important years for me,” he reveals, despite the fact it meant spending his mid-teenage life in a tiny Borders village. “Nobody seemed to have asked anything about me being taken out of school, though sometimes I wish I had had a broader education. We were pretty isolated, but Jane insisted we studied German, some French, some music history and other things. It wasn’t just cello, cello, cello by any means.”

Nonetheless, music was the centre of this isolated universe, and Isserlis found the environment comfortable. “She always made the music make sense. She would create an atmosphere in which you felt the composer was with you like a friend. I think I probably got from her that you don’t do things to music; music does things to you. It should speak through you,” he says of Cowan’s teaching.

At 57 and based in London, Isserlis recalls his Scottish years with warmth. He went on to study in America, and his career has been one marked by consistency, integrity and the odd surprising diversification. He’s written two children’s books – Why Beethoven Threw The Stew and Why Handel Wiggled His Wig – with one “not necessarily for children” possibly on the way.

Musically, he’ll be reacquainting himself this year with the Walton and Elgar concertos, and recording, for a second time, the Bach cello suites “against my better judgement – I got bullied into that.” He’s also revisiting the Beethoven sonatas in America with his old friend Robert Levin on fortepiano. “We’ve been doing that cycle regularly for 11 years,” he says. “It’s almost my favourite thing to do.” For Isserlis, clearly, old friendships are important.

• Steven Isserlis appears with Joshua Bell and the Academy of St Martin in the Fields at the Usher Hall, Edinburgh, tomorrow,www.usherhall.co.uk